He was born in Aker, the son of librarian Wilhelm Munthe (1883–1965) and his wife Jenny Hempel (1882–1975).
The younger Munthe finished his secondary education in 1941, and graduated from the University of Oslo with the cand.oecon.
He was employed as a research fellow at the Norwegian School of Economics and Business Administration in the following year, and was promoted to docent in 1956.
[1] His published works include Freedom of Entry into Industry and Trade (1959), Produsentenes vertikale markedspolitikk som pristeoretisk problem (1960), Horisontale karteller (1961), Sirkulasjon, inntekt og økonomisk vekst (1976, third ed.
He was chairman of Norsk Hydro from 1974 to 1977, Freia from 1978 to 1990, Aschehoug Forlag from 1979 to 1992 and Fritt Ord from 1981 to 2000.